For rolling wire to final gauge, i.e. for calibrating a rolled wire, in a high speed wire mill a plurality of roll units are oriented alternately at right angles to each other and positioned one behind another along the rolling line. The rolls are driven by two roll drive shafts running on opposite sides of the line parallel to it and with a connected dividing gear unit for driving both of the roll drive shafts of a common pair of rolls by a common drive motor.
In the past the connection of the individual roll units to the roll drive shaft has been effected by bevel gears. Thus the gear ratio for the gearing of the rolls can be set to provide the desired rotational speeds which are required for the respective roll units for certain quality materials and/or which result in a series of decreases in caliber of the products. Moreover a predetermined rotational speed ratio of both roll drive shafts to each other results when the gear ratio is set. When other materials are to be rolled and/or other products are to be made, of course, the provided bevel gearing and the rotational speed ratio of both drive shafts remains unchanged. However it is advantageous to change the rotational speed ratio of the roll drive shaft for different operating conditions. Therefore a variety of dividing gear units must be built to handle the variety of required conditions for operation.